As a tape printing device of this type, a printer in which a loading section where a tape housing cassette (tape cartridge) is loaded is provided with a cassette cover (open/close cover) for opening/closing the loading section is known (see JP-A-7-214828).
In the tape housing cassette, three protrusions corresponding to a tape width sensor of the printer are provided. Meanwhile, in the printer, the loading section for the tape housing cassette is provided with a tape width sensor made up of a photointerrupter to detect each of the three protrusions. The tape width sensor detects the tape width of a print tape installed in the tape housing cassette, by detecting the presence/absence of each of the three protrusions. Also, in the printer, a small mechanical switch for detecting the opening/closing of the cassette cover is provided at a position off the loading section.